26 
The late Dr. Jenner 
than the usual time. The same deviation from the ordinary 
course of nature, which prematurely occasions the pairing of 
our domestic birds above-mentioned, proves the stimulus, I 
conceive, to certain unseasonable migrations, and accounts 
for the irregularity first noticed. The same argument is of 
course applicable to the premature appearance of any other 
migrating birds. The month of March sometimes affords 
us warm weather for several successive days. At this time 
I have often seen the snake basking under a hedge. The 
lizard too, has been invited from his cold retreat ; but never 
could I see the swallow or the martin, although I have taken 
every opportunity of looking for them during the transient 
sunshine, and made diligent enquiries of others. At the fur- 
ther advancement of spring, often in April, when, from the 
long prevalence of north-easterly winds, the weather becomes 
unseasonably cold, and even frosty, swallows, martins, and 
other early migrators appear among us. But they soon ex- 
perience the hardships of an inhospitable reception : the 
insects that should afford them food being still in a state of 
torpor in their wintry recesses, and unless called forth by 
some agreeable change in the air, the unfortunate birds perish 
for want of food. This I have known happen during an in- 
clement spring, and have picked up starved martins under 
their nesting places, and willow wrens, which have perished 
under hedges, through a want of succours. 
Unlike the migrating birds that winter with us, of which I 
shall speak in a subsequent part of this paper, the spring or 
summer birds do not possess the disposition to change the 
scene and seek a more genial clime, when this country is so 
overspread by frost as to deny them their common supplies. 
